Hypothetical Heterosis Research Articles

Use of heterosis and transgression events to optimize sizes of leaves in variety group Burley tobacco

The manifestations of heterosis and transgression regarding the length and width of the leaves in ten hybrid combinations of Burley tobacco аre investigated. The results of the study show that in almost all variants and in both indicators, the values of the hypothetical heterosis exceed those of the real one. According to length of leaves heterosis with economic significance is observed only in one of the investigated hybrid combinations. Transgressive manifestations for this indicator are even less pronounced and are not significant in any of the studied options. In contrast to length of leaves the manifestations of heterosis are of economic importance in six of the ten crosses studied and could be successfully used to increase of width of leaves. Transgressive events in width of leaves are less pronounced than heterosis, but much more pronounced than those in the length. Direction of crossing affects the heterosis manifestations only of the length of the leaves but not those concerning their width. In terms to width of leaves, the manifestations of heterosis and transgression are related. Of all the studied variants, the one with the highest selection value regarding sizes of leaves is Hybrid 1555.

Наследяване на стопански ценни признаци и хетерозис при хибридни комбинации зимен ечемик

The article presents the results of the analysis of the inheritance of the main economic valuable traits of barley hybrids of the first generation using indicators of the degree of phenotypic dominance and heterosis. 6 hybrid barley combinations were evaluated according to the following characteristics: plant height (cm), productive twining, length of main spike (cm), number of grains in main spike, grain weight per spike (g), grain weight per plant (g), mass of 1000 grains (g). The research was carried out at the Institute of Agriculture-Karnobat in 2022-2023. Highly productive varieties and samples of barley, Bulgarian selection and from introduction were used as parental forms. For each investigated trait, the arithmetic mean ( x ), the error of the arithmetic mean (S %), variation coefficient (VC,%), the degree of dominance (d/a), true (HP) and hypothetical (MP) heterosis were determined. Based on the variation and inheritance in the early F1 hybrid generations, conclusions were drawn regarding the value of the cultivars used and the type of inheritance of the traits analyzed.

Study of the heterosis effect of morpho-biological traits of grain sorghum hybrids F<sub>1</sub>

The priority direction in grain sorghum breeding is the development of new early maturing, highly productive hybrids adapted to the soil and climatic conditions of the region and their introduction into agricultural production. Thus, the use of the heterosis effect in hybrids developed from maternal lines with cytoplasmic male sterility is of particular interest. The current paper has presented the study results of heterosis of grain sorghum hybrids of the first generation, developed on the basis of CMS lines, according to the main quantitative traits. The trials were carried out in the laboratory for grain sorghum breeding and seed production of the FSBSI «Agricultural Research Center «Donskoy» in 2020–2022. The purpose of the current research was to study the heterosis effect of morpho-biological traits of grain sorghum hybrids of the first generation developed from crossing sterile lines with highly productive varieties and samples of various breeding. In most hybrids, true and hypothetical heterosis were identified according to plant height, weight, and number of grains per panicle, and the frequency of high heterosis values was estimated according to weight and number of grains. The maximum effect of heterosis manifestation was established based on the trait ‘protrusion of a panicle stalk’ in the combination of AZSK21 x ZSK 24/20 (Htrue = 335.0 %; Hhyp = 694.4%). According to the length of a vegetation period during 2020–2022, all combinations turned out to be early maturing and the heterosis effectwas absent in most variants. 65 % of hybrids were classified as undersized, and the highest heterosis in the trait ‘plant height’ was 38.9 %. During the trials, the hybrid ‘Jetta x ZSK 217’ (87.35 g) showed an excess in the trait ‘grain weight per panicle’ over the best parental form. There have been identified the samples that are expedient to use in crossings to obtain highly productive hybrids, such as ‘By 112’, ‘ZSK 196/17’, ‘ZSK 217’, ‘Zhemchug № 56’, ‘Zhemchug № 59’ and ‘B-10434’.

HETEROTIC EFFECTS OF SUGAR BEET (BETA VULGARIS L.) HYBRIDS FOR ROOT YIELD AND SUGAR CONTENT

Hybrids with heterotic effects manifest themselves with a significant enhancement in growth and productivity traits compared with their parental genotypes. However, inbreeding resulted in decreased heterosis. Researchers believe that a noteworthy increase in F1 hybrids for economic and biological attributes is evident due to heterozygosity and overdominance of the corresponding genes of different parents combined in one genotype. The presented study sought to determine the heterotic effects of sugar beet hybrids for economically valuable traits and select the best parental lines with crossing potential for productivity. Five different sugar beet hybrids, analyzed during the crop seasons 2021 and 2022 for accurate and hypothetical heterosis and the degree of dominance in F1 generation for economically valuable traits like productivity and sugar content, transpired at the LLP – Kazakh Research Institute of Agriculture and Plant Growing (KazRIAPG), Kazakhstan. The crossing of the sugar beet line KazMS with pollinators, viz., VP24, VP44, OP17231, OP17232, and OP14044, changed the type of inheritance in hybrids for productivity from negative dominance in variants with pollinators (VP24, OP17231) to overdominance in variants with pollinators (VP44, OP14044). Based on the results, the conclusion indicated that the type of productivity inheritance in F1 hybrids involving the same maternal line differed.

Use of cytoplasmic male sterility in sorghum breeding for productivity

The productivity increase of many agricultural crops is associated with the production of heterotic hybrid forms that are more productive than conventional varieties. In order to obtain a heterotic effect and develop hybrid seeds in sorghum breeding practice, the phenomenon of cytoplasmic male sterility is used. The purpose of the current work was to study new sorghum-Sudan hybrids developed on the basis of CMS, and to determine heterosis according to the main economically valuable traits that affect green mass productivity. The study was carried out in theAgricultural Research Center “Donskoy” in 2020–2022. The objects of the study were the sorghum-Sudanese hybrids studied in the competitive variety testing. Sowing and field observations were carried out according to generally accepted methods. The meteorological conditions during the years of study (2020–2022) varied significantly, which made it possible to conduct a comprehensive estimation of hybrids in contrasting conditions. According to the study carried out according to the main traits (length of “sprouts-heading stage” period, plant height, length of the 3rd leaf and number of leaves per plant), which affect the productivity of sorghum-Sudan hybrids, there has been established a high heterotic effect. Hybrids developed on the basis of CMS had a green mass productivity of 3557–5949 g/m2 for two cuts. Hypothetical heterosis ranged from 59.8 to 144.3 %, true heterosis was 22.1–95.1 %. According to the green mass productivity, the hybrids ‘APV-1115 x Kudesnitsa’, ‘APV-1115 x Svetloplenchataya 2’, ‘APV-1115 x ChT-22’, ‘Dzhetta x ChT-22’ were the best ones, exceeding the standard on 755–1384 g/m2 or by 16.5–30.3 %. The identified hybrids have confirmed the expediency of using cytoplasmic male sterility to obtain a highly heterotic effect both in terms of green mass productivity and in terms of the main traits that affect productivity.

Characteristics of interline table watermelon F<sub>1</sub> hybrids according to the degrees of dominance and indices of true and hypothetical heterosis

Background. Heterosis is one of the most important and promising plant breeding trends. Its development will make it possible to obtain hybrids with high adaptability and a high heterosis effect in their quantitative and qualitative characteristics.Materials and methods. The studies were carried out under dry conditions of the Volgograd Trans-Volga region in 2019–2020. Heterotic hybrids of table watermelon served as the research material, and hybridization and inbreeding as research methods. The heterotic F1 hybrid of watermelon Barkhan was used as the reference.Results. The characteristics of heterotic watermelon hybrids were compared with the parental forms and the Barkhan F1 reference. The length of the growing season in heterotic hybrids was inherited intermediately. In the average fruit weight, the reference was exceeded by the hybrids ChmsMt and ChmsFt by 1.1 kg. The highest average yield for the two years of research was observed in the F1 hybrids ChmsNts (24.3 t/ha), ChmsFt (24.1) and ChmsMt (23.1) (reference: 20.8 t/ha). The inheritance of fruit weight according to the principle of overdominance occurred in the F1 hybrids ChmsMk, ChmsRn, ChmsNts and ChmsMt. In their fruit weight, the same hybrids showed positive indices of hypothetical and true heterosis. The F1 hybrids ChmsFt, ChmsNts and ChmsIR demonstrated high degrees of dominance in yield (1.8 to 5.0%). The index of hypothetical heterosis had positive results in all studied heterotic watermelon hybrids. Negative true heterosis (–0.49%) was observed in two F1 hybrids, ChmsRn and ChmsPH. The remaining watermelon hybrids had positive true heterosis indices that ranged from 2.4% in ChmsIR to 11.06% in ChmsFt.Conclusion. As a result of the studies, heterotic hybrids of watermelon, developed on the basis of the sterile mother line Chms, were identified for high indices of true and hypothetical heterosis in fruit weight and yield parameters.

Evaluation of the degree of dominance and heterosis effect of table watermelon according to the main economic characteristics

. Heterotic selection is now widely used in crop production. The superiority of heterotic hybrids over varieties in many respects has long been known. However, the widespread use of heterosis in melon growing is hampered by the high cost of seed material, due to the lack of lines with male sterility. The aim of this work was to evaluate heterotic hybrids of watermelon obtained on the basis of a line with male sterility isolated at the Bykovskaya Experimental Station.Materials and methods. The studies were carried out in 2020 and 2021. at the Bykovskaya melon breeding experimental station - a branch of the FGBNU FNTSO. The object of research is heterosis hybrids of watermelon. The heterosis hybrid of watermelon Barkhan was used as a standard. Classical breeding methods were used in the work: incubation and hybridization.Research results. The assessment of watermelon hybrids according to the main economic characteristics revealed the best combinations in comparison with the standard. According to the content of dry matter, four hybrids of watermelon stood out, the excess over the standard ranged from 0.6 to 1.9%. The indicator of the average weight of the fetus in one LIR hybrid was at the level of the standard and amounted to 6.5 kg. The remaining hybrids exceeded the Barkhan standard by 1.2-4.0 kg. The average yield of the studied hybrids ranged from 19.0 to 22.5 t/ha. The calculation of such indicators as the degree of dominance, the effects of true and hypothetical heterosis made it possible to identify three combinations with high rates.Conclusion. Thus, it was found that the yield in heterotic hybrids of watermelon is inherited according to the principle of overdominance. Inheritance of traits dry matter content and average fruit weight ranges from minus overdominance to overdominance in various combinations. According to the complex of economically valuable traits, three combinations of table watermelon were distinguished: LKn, LMr and LFT.

Manifestation of Heterosis and Degree of Phenotypic Dominance by the Number of Grains from the Main Ear in the Hybridisation of Different Early-Maturing Varieties of Soft Winter Wheat

Winter wheat (Triticum aestivum L.) is the main food crop on a global scale, in the growth and stabilisation of yields, of which varietal resources are a significant factor. In practical breeding work, an essential role is played by a variety of thoroughly investigated source material. The purpose of this study was to determine hypothetical and true heterosis and establish the nature of inheritance of the number of grains from the main ear in hybrids of soft winter wheat. In 2018-2020, 45 combinations of cross-breeding of soft winter wheat varieties obtained from hybridisation of different growing season periods were investigated in the experimental field of the Research and Production Centre of the Belotserkovskyi National Agrarian University. Generally accepted methods were used to determine the hypothetical and true heterosis and the degree of phenotypic dominance by the number of grains in the main ear. Studies indicate that the number of grains in the ear of the main stem of the parent components of hybridisation is determined by genotype and considerably depends on the hydrothermal conditions of the year. The author of this paper established the influence of maternal cytoplasm on the manifestation of the trait under study. Thus, when used in hybridisation of early-maturing varieties with the mother form, the largest average number of grains in the main ear for hybrids (63.3 pcs.) was formed in 2019. At the same time, for the use of medium-early, medium maturing, and medium-late varieties in hybridisation, the maximum number of grains (64.8 pcs.) was marked in 2018. Therewith, all hybrids formed the minimum number of grains in 2020. The obtained experimental data indicate the influence of parental genotypes and year conditions on heterosis indicators and the degree of phenotypic dominance in first-generation hybrids. It is determined that the most common type of inheritance (85.6%) of the number of grains from the main ear is positive overdomination. Practical value for the selection of soft winter wheat are the selected cross-breeding combinations: Myronivska early / Zolotokolosa, Myronivska early / Cherniava, Bilotserkivska semi-dwarf / Cherniava, Bilotserkivska semi-dwarf / Antonivka, Kolchuha / Antonivka, Zolotokolosa / Charniava, Zolotokolosa / Yednist, Cherniava / Vidrada, Cherniava / Stolychna, Shchedra Nyva / Dobirna, Antonivka / Stolychna, Dobirna / Pyvna, which significantly exceeded the average number of grains from the main ear for F1 in the changing fields under hydrothermal conditions the years of research

THE LEVEL OF HETEROSIS AND THE DEGREE OF PHENOTYPIC DOMINANCE OF THE MAIN ECONOMICALLY VALUABLE CHARACTERISTICS IN F1 HYBRIDS OF THE SILKWORM (BOMBYX MORI L.)

There were presented the results of heterosis level (hypothetical and true) and the degree of phenotypic dominance of the main economically valuable characteristics in hybrids of silkworm Bombyx Mori L. of the first generation. The crossing was conducted by full diallel scheme, including 16 variants (12 hybrids and 4 parental forms), 50 mg in triplicate replications. There were studied the types of heredity and the level of heterosis of the main economically valuable characteristics in F1 hybrids of silkworms. It was revealed that the heredity of caterpillars viability, average cocoon weight and male silkiness was mostly positive as regards to G2, G4, G6 and G7 lines, while the heredity of females was mostly depressed (negative superdominance). Determination of the effect of heterosis and the degree of phenotypic dominance made it possible to identify 7 best combinations in terms of caterpillar viability in comparison with parental forms, among them the best were hybrids G2×G6 and G6×G2 with high degree of phenotypic dominance (positive superdominance) -- 7.8 and 9.0, with hypothetical heterosis of 11.0% and 12.7% and true heterosis of 9.4% and 11.1% accordingly. The effect of heterosis (positive superdominance) was found in 8 hybrids according to cocoon weight out of 12 hybrid combinations, partial positive inheritance in 3 hybrids, and intermediate type of dominance in 1 hybrid. The hybrids G6×G4 (Ht=9.00 %, Hbt=8.30 %) and G6×G7 (Ht=1.68 %, Hbt=1.43 %), whose heredity was of the positive superdominance type, were distinguished by female silkiness with a high level of hypothetic and true heterosis (13, 92 and 6.80, accordingly), while hybrid depression was observed in 5 combinations, intermediate heredity in 3, and partial positive and negative dominance in one combination each. The 9 hybrids had positive overdominance type heredity for silkiness in males. Production of high-quality silkworm biomaterial contributes to extension of possibilities of its use in various spheres of human activity.

Inheritance of resistance of spring barley to Erysiphe graminis f. sp. hordei in F1 and variability in F2 in the conditions of the Right-Bank Forest-Steppe of Ukraine

The nature of the inheritance of resistance to Erysiphe graminis f. sp. hordei in the crosses of genotypes of spring barley in F1 and transgressive variability in F2 populations are investigated. Inheritance of the trait of resistance to Erysiphe graminis f. sp. hordei in F1, by hybridization of genotypes of spring barley with known genes of resistance to Erysiphe graminis f. sp. hordei in European varieties Eunova (mlo11) and Barke (mlo9), which are located on chromosome 1H, was positively dominated. Inheritance of the F1 trait in Aspen (mlo11) and Adonis (mlo9) cultivars was partially positive. The influence of parental pairs for hybridization on the indicators of the degree of phenotypic dominance, hypothetical and true heterosis was established. Resistance to Erysiphe graminis f. sp. hordei in F1 hybrids was observed heterosis (positive dominance) in fve hybrid combinations (hp = 1.1–1.9 %): Barke/Badoryi, Barke/Sanktrum, Parnas/Rostentsii, Badoryi/ Barke, Eunova/Zvershennia. Hypothetical heterosis (Ht) in F1 was observed in 13 of 16 hybrids (from +2.8 % to +97.6 %). A positive value of true heterosis (Htb) in F1 was observed in 15 hybrids out of 16 (from +1.9 % to +98.8 %). Inheritance of the trait of resistance to Erysiphe graminis f. sp. hordei in all studied hybrids was influenced by the cytoplasm of the mother plant, except for the hybrid Eunova / Triangel, where the influence of the nuclear apparatus was detected. Hybrids were found in the F 2 population with high resistance to Erysiphe graminis f. sp. hordei, which exceeded the parental components, which indicates a signifcant shaping process and the possibility of selection on the basis of the studied trait. The degree of positive transgression ranged from 16.0 % to 73.0 % in hybrids Aspen / Skarlet, Adonis / Vanja, Barke / Badoryi, Barke / Sanktrum, Eunova / Triangel and Eunova / Zvershennia, where highly resistant varieties were used for the mother form. The combinations in which the frequency of transgression was observed in more than 50.0 % of plants are hybrids: Eunova / Triangel, Barke / Sanktrum, Eunova / Zvershennia, Parnas / Rostentsii and Barke / Badoryi. Key words: spring barley, resistance, Erysiphe graminis f. sp. hordei, combinations of crossing, inheritance, F1, true and hypothetical heterosis, degree of phenotypic dominance, F 2, degree and frequency of transgressions.

Features of heterosis manifestation in interlinear hybrids of sweet pepper in unheated film greenhouses

The dynamics of changes in an important economic trait of sweet pepper “average fruit weight” and the manifestation of heterosis have been studied on the example of 10 hybrids and their parental lines with multiple harvests in an unheated film greenhouse. It was found that the average weight, regardless of its value, was maximum and relatively stable during the first 5 harvests, which corresponds to the return of an early yield in the first month of fruiting. At the last collection, there was a decrease in the average weight of the fruit by 1.3-2.5 times. It has been established that a decrease in fruit weight with late harvests in hybrids occurs at a later date and is less pronounced than in parental lines, which indicates their higher adaptive ability. With an early harvest in 3 combinations, the level of true heterosis was 5.4-19.7%, a hypothetical heterosis at the level of 5.4-24.4% was found in 7 hybrids. At an early harvest and a late harvest in 50% of sweet pepper hybrids, the value of heterosis varied, but had the same character; in 50% of hybrids, a change in the sign of heterosis to the opposite was noted.2 hybrid combinations with a more stable average fruit weight were identified with multiple harvests - (Bs1xF46Kt22706) and (San1xF46Kt2181) with varying traits within 77-99 g and 81-123 g. the effect in 80% of large-fruited (17.6-27.3%) and medium-fruited hybrids (8.5-49.3%) was noted after the early harvest on July 21.The maximum effect of heterosis does not correspond to the maximum value of fruit weight in the experiment and is associated with a more pronounced reaction of the parental lines compared to hybrids to extreme temperatures during the period of fruit formation.

Inheritance in F1 and transgressive variability in F2 of the main ear length by crossing wheat varieties with different maturity

In 2017–2019, the nature of the inheritance of ear length in F1 and transgressive variability in F2 populations obtained by hybridization of soft winter wheat varieties with different maturity were studied. It was found that in most combinations of crossbreeding, inheritance of ear length had a positive overdominance (hp = 1.1–39.0). A positive hypothetical heterosis was determined in early-maturing varieties in the maternal form, with the exception of the Kolchuga / Chornyava combination, by the length of the main ear (Ht = 3.6–44.8 %). a positive true heterosis (Hbt=1,1–32.9 %) was found in 15 of 20 hybrids. During the hybridization of medium-early, medium-ripe and medium-late varieties, all hybrids showed a positive hypothetical heterosis and 19 of 22 combinations had positive true heterosis. A significant influence of hybridization components on the indicators of the phenotypic dominance degree, hypothetical and true heterosis was established. Most of the F2 populations significantly exceeded the parental components of hybridization by the extreme maximum indexes of the main ear length, which indicates a significant shaping process and the possibility of selection on the basis of the studied trait. The maximum length of the main ear (10.3–12.1) was formed by most populations in which the maternal forms were varieties Kolchuga and Chornyava, as well as combinations Zolotokolos / Chornyava, Zolotokolosa / Stolychna and Yednist / Vidrada. The extreme maximum values reached 13.0–15.0 cm. In 36 of the 42 F2 populations, a positive degree and frequency of transgressions by the length of the main ear were determined, and their indexes largely depended on the pairs selection for hybridization. The highest degree of positive transgression was observed in the population Yednist / Vidrada (44.4 %) with a recombinant frequency of 86.7 %. Populations were characterized by a high degree and frequency of positive transgressions: Kolchuga / Yednist; Myronivska early / Antonivka; Myronivska early / Vdala; Zolotokolosa / Vidrada; Dobirna / Pyvna; Zolotokolosa / Stolychna; Zolotokolosa / Shchedra nyva; Myronivska early / Yednist; Myronivska early / Zolotokolosa; Myronivska early / B.Ts. n / a. Key words: soft winter wheat, maturity of varieties, combinations of crossbreeding, inheritance, hybrids, ear length, hypothetical and true heterosis, degree of phenotypic dominance, F2 populations, degree and frequency of transgressions.

Transcriptome and genome sequencing elucidates the molecular basis for the high yield and good quality of the hybrid rice variety Chuanyou6203

The yield heterosis of rice is sought by farmers and strong contributes to food safety, but the quality of hybrid rice may be reduced. Therefore, developing new varieties with both high yield and good quality is a heavily researched topic in hybrid rice breeding. However, the molecular mechanism governing yield heterosis and high rice quality has not been elucidated to date. In this study, a comparative transcriptomics and genomic analysis was performed on a hybrid rice variety, Chuanyou6203 (CY6203), and its parents to investigate the molecular mechanism and gene regulation network governing the formation of yield and quality stages. A total of 66,319 SNPs and InDels between CH3203 and C106B were detected in the 5′-UTR, exon, intronic, and 3′-UTR regions according to the reference genome annotation, which involved 7473 genes. A total of 436, 70, 551, 993, and 1216 common DEGs between CY6203 and both of its parents were identified at the same stage in panicles and flag leaves. Of the common DEGs, the numbers of upregulated DEGs between CY6203 and CH3203 were all greater than those of upregulated DEGs between CY6203 and C106B in panicles and flag leaves at the booting, flowering, and middle filling stages. Approximately 40.61% of mRNA editing ratios were between 0.4 and 0.6, and 1.68% of mRNA editing events (editing ratio ≥ 0.8) in CY6203 favored one of its parents at three stages or a particular stage, suggesting that the hypothetical heterosis mechanism of CY6203 might involve dominance or epistasis. Also 15,934 DEGs were classified into 19 distinct modules that were classified into three groups by the weighted gene coexpression network analysis. Through transcriptome analysis of panicles and flag leaves in the yield and quality stages, the DEGs in the green-yellow module primarily contributed to the increase in the source of CY6203 due to an in increase in photosynthetic efficiency and nitrogen utilization efficiency, and a small number of DEGs related to the grain number added spikelet number per panicle amplified its sink. The balanced expression of the major high-quality alleles of C106B and CH3203 in CY6203 contributed to the outstanding quality of CY6203. Our transcriptome and genome analyses offer a new data set that may help to elucidate the molecular mechanism governing the yield heterosis and high quality of a hybrid rice variety.

Прояв і мінливість біометричних ознак у ліній–батьківських компонентів та гібридів кукурудзи за використання різних генетичних плазм при зрошенні

Прояв і мінливість біометричних ознак у ліній–батьківських компонентів та гібридів кукурудзи за використання різних генетичних плазм при зрошенні

The efects of heterosis of the sorghum hybrids F1 based on cytoplasmic male sterility

Currently, the development of highly productive sorghum hybrids with a high content of the main nutritional components in grain is of great relevance. The current paper has presented the estimation results of the effects of true and hypothetical heterosis on percentage of protein, oil and starch in grain of the first-generation hybrids. There have been analyzed 54 combinations obtained on the basis of three CMS-lines and 18 pollinators. The components of the hybrids and their progeny were grown on the FSBSI RosNIISK “Rossorgo” experimental plots of 7.7 m2, in triple sequences with plant density of 100 thousand plants per ha. The biochemical composition of the grain was determined by the SpectraStarXT infrared analyzer. The parental components and their progeny differed in the biochemical composition of grain, which was confirmed by the analysis of variance. There was identified a slight variation of the ЗерновоехозяйствоРоссии № 2(68)’ 2020 50trait ‘starch content’ in maternal and paternal forms of the hybrids F1(V= 2.5–8.3%). There was identified an average variability of protein percentage in the initial forms (V= 7.9–14.6%) and a weak variability in hybrids (V= 9.1–10.8%). There were identified larger values of variation of oil content (9.0–17.2%). The manifestation frequency of true and hypothetical heterosis of protein percentage was identified in 31.5–62.9% and 44.4–79.6% of hybrids; of fat content was identified in 20.4–57.4% and 20.4–75.9% of hybrids; of starch content was identified in 16.6–33.3% and 16.6–44.4% of hybrids. A focused approach in breeding the varieties with the improved biochemical components of grain allowed us to identify 9 combinations characterized by the annual effect of heterosis in protein content (4 combinations), in raw oil accumulation (2 combinations) and in starch accumulation (3 combinations).

Iodent Germplasm Source Material Selection in Development of Maize Hybrids for the Steppe Zone of Ukraine

The aim of the study: Evaluation of sister hybrids obtained on the basis of early maturity Iodent germplasm inbred lines (FAO 180-250) as a source material for the development of new inbred lines and evaluation of this material’s main breeding qualities as well as of level of hypothetical heterosis in sister crosses and their polymorphism as an integral part of the breeding cycle. Methods: Field method, mathematical-statistical method. Results: The studies investigated sister hybrids obtained by crossing of 8 precocious Iodent germplasm inbred lines, their combining ability for “grain yield” trait and determined whether they can be used as a source material for the synthesis of new homozygous inbred lines. The results of the evaluation of sister hybrids and their testcrosses on the basic economically valuable traits are presented. According to research results in 2013-2015, it was found that sister hybrids with the least variable grain yields by years of research were obtained from the crossing of DK1274 and DK237 inbred lines. The calculations of the correlation coefficients between hypothetical heterosis and genetic distances revealed no significant correlation between them (r=0.118-0.359) as well as between the yield of sister hybrids and genetic distances (r=0.167-0.351). It was found that the least variable indicators of grain yield for the years of research were noted in sister hybrids obtained on the basis of source inbred lines with the most stable manifestation of this indicator (r=0.714). Sister hybrids were noted, which had effects of general combining ability at class 2, regardless of study conditions (DK216 × DK213, DK237 × DK1274, DK714/195 × DK216), indicating the stability of genotype response to growing conditions. Conclusion: The evaluation of 8 precocious constant Iodent germplasm inbred lines on breeding traits revealed the best of them (DK555 and DK1274) in combining ability compared to the DK744 control inbred line. Significant influence of the conditions of research years on all the traits studied was noted. The study of sister hybrids has revealed forms with a significant manifestation of hypothetical heterosis. It was the highest on average in crosses of inbred lines DK234 (137.0%), DK714/195 (122.7%) and DK216 (101.1%), and the smallest in hybrids with inbred lines DK555 (58.5%), DK1274 (65.8%) and DK744 (75.0%). Sister combinations with DK1274 and DK237 inbred lines were characterized by the highest yield stability over the years of study. In determining genetic distances, the most genetically similar inbred lines DK744 (0.136) and DK234 (0.197) to inbred line 207 (P165), which is the classic representative of the Iodent germplasm, are noted.

The study of the nature of the inheritance of quantitative traits in F1 hybrids of winter soft wheat

In the conditions of the south of the Nonchernozem Zone, intraspecific hybridization of winter soft wheat was carried out. When selecting parental forms used in crossing, special attention was paid to such economically valuable traits as productive tilling capacity, the number of grains and the mass of grain per spike. The true (Htru) and hypothetical heterosis (Hhyp) on the basis of “plant height”, “length of the lower internode”, “length of the upper internode”, “general tilling capacity”, “productive tilling capacity”, “spike length”, “number of spikelets”, “number of grains” and “grain weight per spike” were determined. It was established that the inheritance of quantitative traits in hybrids of the first generation was distinguished by the complex nature of distribution by types. Studies have made possible to identify 5 hybrid combinations F1, in which the effect of heterosis manifests itself simultaneously on five quantitative characteristics (ear length, number of spikelets per ear, number of grains per ear, grain weight per ear, mass grain from a plant).

Хетерозисни прояви по технологични параметри в F1 хибриди лук за сушене

The suitability of newly developed F1 onion (Allium cepa L.) hybrids for drying was evaluated in 3-year experiment by the expression of the heterosis effect toward the time for reaching to the minimal equilibrium moisture content during the drying process. Lines, varieties and F1 onion hybrids of three types (hot, semi-hot and sweet) with yellow envelope flakes and different morphological characteristics were used. The drying time for the investigated variants ranged between 70 and 180 minutes. The bulbs of hybrid Liaskovski sterile x Jubilei 50 (LA x J50) F1 were dried most rapidly. The hypothetical heterosis varied from -17.65% to 46.67%. Heterosis manifestations concerning drying time of onion bulbs were expressed but they have not economic importance. Therefore the heterosis breeding is not the way for increasing the suitability of onion for drying. Systematic investigations on the initial plant material before including in the hybridization in order to search parental components with optimal values of the drying parameters have to be on the focus.

Inheritance pattern of plant height in F1 Triticum aestivum L. using wheat-rye translocations in conditions of the Central Forest-Steppe of Ukraine

Purpose. To find out the inheritance pattern of plant height in the F1 hybrids from crossing varieties of Triticum aestivum L. which are carriers of wheat-rye translocations (WRT). Methods. The research was conducted in 2016-2017 at the V. M. Remeslo Myronivka Institute of Wheat (MIW) on 30 hybrid combinations of varieties-carriers of wheat-rye translocations. The degree of phenotypic dominance of plant height was determined by the formula B. Griffing; grouping was by G. M. Beil, & R. E. Atkins; manifestation of heterosis was by D. F. Matzinger et al. and S. Fonseca, F. Patterson. Results. The manifestation of depression in plant height in dry season of 2017 was established for almost quarter (seven) of hybrids, while in more favorable meteorological conditions of 2016 there was overdominance of short-stem in hybrid combinations: Kalynova 1BL.1RS / Lehenda Myronivska 1BL.1RS, Zolotokolosa 1AL.1RS / Kolumbiia 1AL.1RS, and Kolumbiia 1AL.1RS / Zolotokolosa 1AL.1RS. In 2017, one hybrid combination was characterized by partial negative inheritance. Regardless of the weather conditions of the year, positive overdominance (increase in plant height) was observed in six hybrid combinations which had high values of the coefficients of both true and hypothetical heterosis. The excess of the height of hybrid plants above the average value of this indicator of both parents was noted in 2016 in 73.3 % of the studied hybrid combinations, and in the unfavorable 2017 it was in 63.3 %. More cases were noted in the 1AL.1RS / 1BL.1RS and 1BL.1RS / 1AL.1RS crosses. Heterosis in plant height was determined for almost half of the hybrid combinations in the groups of crosses 1AL.1RS / 1BL.1RS (for two years) and 1BL.1RS / 1AL.1RS (in 2016). For two years depression of the trait “plant height” was found in hybrids created by using the variety Kolumbiia 1AL.1RS as maternal form when crossing with the variety Zolotokolosa 1AL.1RS, as well as in the hybrid combination Kalynova 1BL.1RS / Lehenda Myronivska 1BL.1RS. Conclusions. The use in crosses of varieties-carriers of WRT differing in plant height made it possible to obtain a different degree of dominance in F1: from overdominance (heterosis) to depression.

Heritability and number of genes controlling seed yield in bottle gourd

Bottle gourd [Lagenaria siceraria (Molina) Standley] is an important tropical specie characterised by a wide diversity and a low yield, mainly due to no selection for improved varieties. Selection for a particular trait depends on the relative importance of genetic and nongenetic factors influencing the expression of phenotypic differences among crop population. The objective of this study was to examine the genetics basis of seed yield and yield components, by crossing oleaginous type and calabash-type of bottle gourd [Lagenaria siceraria (Molina) Standley]. The parental lines (P1 and P2), with the respective hybrids F1 and F2 generations, were grown in two contrasted locations in terms of pedoclimatic conditions. Results showed no significant difference between the two locations for studies traits (P=0.06). For seed yield per plant, 100-seed weight per fruit, and number of seeds per fruit, a positive hypothetical heterosis was observed when calabash type was a maternal parent. Negative real heterosis was observed in all studied traits. For all traits, the genetic variance was higher than the environmental variance in the most of the crosses, implying greatest genes action in the expression of studies traits. Heritability was medium for fruit weight (mean, 42.12%) and seed number per fruit (mean, 47.36%). But for 100-seed weight (mean, 61.00%) and seed yield per plant (mean, 53.28%) high heritability were observed. The minimum number of genes that controlled the expression of 100-seed weight (0.58), seed yield per plant (1.58) and number of seeds per plant (0.98) was low (close to 1). These observations suggest that distinct genotypes for interest characters would be fixed by using a small number of selfing generations (F3 to F4) in West African bottle gourd. Key Words: Heritability, heterosis; Lagenaria siceraria, number of genes, seed yield